1. Field of the Invention
The present invention generally relates to a combination weighing apparatus for performing a combination weighing of articles and, more particularly to a dispensing table assembly employed in such combination weighing apparatus.
2. Description of the Prior Art
A combination weighing apparatus used for weighing various types of articles generally includes a dispensing table assembly distributing the articles to be weighed, supplied from above by the effect of gravity, over the dispensing table assembly, a plurality of troughs arranged in a pattern radially of and below an outer peripheral edge of the dispensing table assembly, a plurality of pooling hoppers arranged in a circular row and positioned immediately below respective front ends of the troughs, and a corresponding number of weighing hoppers positioned immediately below the respective pooling hoppers. The weighing hoppers when receiving the articles from the dispensing table assembly through the troughs and pooling hoppers perform weighing of the articles to determine respective weights of the articles within the respective weighing hoppers so that a combination calculation can be performed using the weights of the articles measured respectively within the weighing hoppers in such a way as to select an optimum combination of articles in which the sum of the measured weights of those articles meets or closely approximate to a target weight or number. The articles, of which weights have satisfied the optimum combination, are subsequently discharged from the associated weighing hoppers onto a collecting chute to eventually provide products satisfying the target weight.
In this type of the combination weighing apparatus, it is necessary for a predetermined quantity of the articles to be weighed to be supplied and distributed from the dispensing table assembly onto the troughs. By way of example, if the articles are unable to be supplied from some troughs towards associated weighing hoppers, such weighing hoppers will be excluded from the combination calculation, and if the number of the weighing hoppers excluded from the combination calculation is many, it may occur that a predetermined weight condition to be satisfied during the combination calculation will not be satisfied, resulting in reduction in weighing accuracy and efficiency. Also, if even though the articles are satisfactorily supplied, the amount of the articles so supplied to some weighing hoppers is extremely small, selection of the weighing hoppers for the combination calculation would be difficult, resulting in stagnation of the articles within such some weighing hoppers for a substantial length of time. In particular, where the dispensing table assembly is divided into a plurality of dispensing tables so that the different kinds of the articles are weighed simultaneously, respectively, it will become necessary to employ partition walls secured to respective divided edges of the dispensing tables for preventing some of the articles supplied onto one of the dispensing tables from entering the other of the dispensing tables and, also, to generally vibrate those dispensing tables. When the dispensing tables are so vibrated, the articles collide with the partition walls and then jump backwards to such an extent as to result in an insufficient amount of the articles being supplied onto some of the troughs in the vicinity of the divided edges of the dispensing tables and, hence, an insufficient amount of the articles are supplied into the respective weighing hoppers, thereby posing a detrimental problem.
In order to cope with the above discussed problem, the Japanese Laid-open Patent Publication No. 8-54278 discloses a combination weighing apparatus which employs a cone-shaped dispensing table assembly divided into two halves, each comprised of a generally sector shaped dispensing table. Each of the resultant dispensing tables has a partition wall secured to a divided edge thereof for preventing some of the articles to be weighed dispensed onto one of the dispensing tables from entering the other of the dispensing tables. Each of the dispensing tables has an angle of inclination along a generatrix of the surface on which the articles are dispensed, which angle of inclination is continuously varied in a circumferential direction so that the greatest angle of inclination is attained in the vicinity of an outer end of the partition wall and the smallest angle of inclination is attained on the generatrix of the article dispensing surface positioned at an intermediate location as viewed from the site where the greatest angle of inclination is defined. By so designing, the articles to be weighed can be uniformly delivered even onto troughs positioned adjacent the partition walls.
However, it has been found that the combination weighing apparatus disclosed in the above mentioned publication has a problem. Specifically, despite the fact that the distributing point represented by a vertex of the respective dispensing table is defined at a location adjacent the divided edge, two supply members for supplying the articles onto the associated dispensing tables cannot be disposed immediately above the associated distributing points for avoiding any possible mixing of the articles on those dispensing tables and, therefore, the two supply members have no way other than to be disposed in side-by-side relation with each other in a horizontal direction. In this arrangement disclosed in the above mentioned publication, the supply members that ought to be positioned immediately above the distributing points, respectively, have their centers of supply that are separated in a radial direction perpendicular to the partitioning walls and, as a result thereof, most of the articles falling from the supply members onto the dispensing tables tend to be biased in a direction of the greatest inclination at a falling position and will not be sufficiently distributed from the falling position towards the partition wall. Accordingly, the surface area of each of the dispensing tables is reduced by a quantity corresponding to the thickness of the associated partition wall and the amount of the articles to be supplied towards the troughs positioned adjacent the partition wall where the amount of the article is small is further decreased, resulting in insufficient supply of the articles towards such troughs.
Also, even if the dispensing tables are circumferentially vibrated by respective vibrating mechanisms to move the articles toward the partition wall in a circumferential direction, some of the articles colliding with the partition wall may be repelled backwardly by the partition wall and will not stagnate in the vicinity of the partition wall.
In view of the foregoing, the present invention is intended to provide a combination calculating apparatus employing a dispensing table assembly which is divided into a plurality of dispensing tables with partition walls, each secured to a divided edge of each of the dispensing tables, wherein each of the dispensing tables is so designed as to allow articles to be weighed to be uniformly dispensed even to an area adjacent the partition wall so that the articles can eventually be delivered onto a plurality of troughs uniformly.
In order to resolve the above discussed problems, the present invention is featured in the following construction.
In the first place, the present invention is featured in a combination weighing apparatus which includes a generally round dispensing table assembly, a plurality of article delivery devices arranged below and radially of an outer peripheral edge of the dispensing table assembly for receiving articles to be weighed from the dispensing table assembly, and a corresponding number of weighing devices disposed below respective front ends of the delivery devices. The dispensing table assembly is comprised of a plurality of divided dispensing tables obtained by dividing the dispensing table assembly across a geometric center thereof, and at least one of the dispensing tables includes a partition wall secured to a cut edge thereof, which is left along a line of division of the dispensing table assembly, so as to extend upright. The at least one dispensing table also includes a distributing point defined at a location spaced a distance from the partition wall for distributing the articles, supplied from above the dispensing table assembly, over the dispensing table. This at least one dispensing table further includes an inclined surface area that is inclined downwardly from the distributing point towards the partition wall.
The distributing point referred to above is the point at which the articles to be weighed are distributed and is not always aligned with the point at which the articles being supplied fall.
According to this invention, the articles supplied from above onto the dispensing tables are dispensed towards the plural article delivery devices while falling along the dispensing tables and are then supplied to the plural weighing devices.
In such case, each of the dispensing tables has the distributing point defined at a location distant from the partition wall for distributing the articles supplied from above towards a peripheral region of the respective dispensing table and inclined surface areas inclined downwardly from the distributing point towards the partition wall. Accordingly, the articles to be weighed which have fallen onto the dispensing tables are assuredly distributed over the inclined surface areas towards respective regions adjacent the partition walls. This is particularly advantageous in that there is no possibility of shortage of the amount of the articles eventually delivered onto the delivery devices positioned adjacent the partition walls and, therefore, the articles to be weighed can be substantially uniformly distributed to the plural delivery devices.
Also, even if, for example, some of the articles to be weighed when the dispensing tables are vibrated in a circumferential direction collide with the associated partition walls and are then repelled backwardly towards the peripheral region, the provision of the inclined surface areas inclined downwardly towards the partition walls is effective to allow such some of the articles, once repelled backwardly in contact with the partition walls, to be again repelled towards the partition walls so as to fall along the inclined surface areas towards the partition walls. For this reason, there is no possibility that the amount of the articles adjacent the partition walls will decrease as a result of repellent in contact with the partition walls.
It is to be noted that the distributing point of each of the dispensing tables referred to above may not be always defined at the highest position of the respective dispensing table, provided that it serves as the point at which the articles to be weighed that are supplied from above by the effect of gravity can be distributed.
In one embodiment of the present invention, the dispensing table has a plurality of downwardly-inclined surface areas defined by a corresponding number of lines of division that extend from the distributing point towards an outer peripheral edge of the dispensing table, wherein at least some of the plural surface areas which deliver some of the articles towards the corresponding delivery devices are inclined at an virtually equal angle with respect to each other.
Also, since each of the dispensing tables is provided with the a plurality of the downwardly-inclined surface areas defined by a corresponding number of the lines of division that extend from the distributing point towards the outer peripheral edge of the respective dispensing table, some of the plural surface areas which deliver some of the articles towards the corresponding delivery devices being inclined at an virtually equal angle with respect to each other, there is no possibility of the articles being biased towards particular surface areas which would occur when each dispensing table has surface areas of different angles of inclination and the articles can therefore be substantially uniformly dispensed.
Preferably, the surface areas that adjoin the partition wall lie substantially perpendicular to the partition wall.
According to this construction, since the surface areas adjoining the partition wall lie substantially perpendicular to the partition wall, there is no possibility that the articles dispensed to those surface areas through the surface areas that are inclined downwardly towards the partition wall are urged against the partition wall and therefore stagnate in the vicinity of the partition wall to such an extent as to move little, and such articles can move smoothly towards the peripheral edge.
In a preferred embodiment of the present invention, a plurality of vibrating mechanisms operable to vibrate the associated dispensing tables, respectively, are employed and each of the vibrating mechanisms has a center of vibration that is aligned with a center of gravity of the associated dispensing table.
According to this preferred embodiment, since each of the dispensing tables is stably vibrated substantially about the center of gravity thereof, further uniform dispensing of the articles to be weighed is possible.
Preferably, each of the vibrating mechanisms is operable to vibrate the associated dispensing table up and down.
According to this construction, since the articles on the dispensing tables are vibrated up and down, even though some of the articles to be weighed collide with the partition walls, components of force repelling some of the articles away from the partition walls are small and, accordingly, it is possible to suppress reduction of the amount of the articles in the vicinity of each of the partition walls.
Also, in another embodiment of the present invention, each of the dispensing tables is formed by a bent plate member.
With this structure, since each of the dispensing tables is formed by bending the plate member, not only can a process be simplified, but the cost of the processing can also be reduced.
Also, since each of the dispensing tables so formed is defined by a combination of surface areas, it is possible to form surface areas appropriate to the various delivery devices and, therefore, there is no possibility of occurrence that the articles are distributed unequally.
According to a further embodiment of the present invention, a supply member for supplying the articles to be weighed towards the distributing point is employed and has a center of supply of the articles being positioned above the distributing point.
In the meantime, in view of the fact that by the present invention the distributing point is defined at a location spaced from the divided edge of the respective dispensing table, it has now become possible to dispose immediately above the respective distributing points the supply members for supplying the articles to be weighed onto the dispensing tables by the effect of gravity, with respective centers of supply aligned with the associated distributing points. Accordingly, with the structure according to the further embodiment, in view of the fact that the articles to be weighed fall towards the distributing points of the associated dispensing tables, the articles to be weighed so supplied can be further uniformly dispensed.
Preferably, a top of each of the supply members represents an inverted conical shape.
With this structure, since the top of each of the supply members has an inverted conical shape, it is possible to render each supply member to have an opening at a lower height than that of the supply member of a type in which the opening can have no way other than to be enlarged in a lateral direction, and therefore, the space for installation can be reduced.